Growth and current–voltage characterization of ZnTe/CdTe heterojunctions

ZnTe layers have been grown on a (111) oriented CdTe single crystal substrate by vacuum thermal evaporation technique. The growth temperature was 180 °C at a base pressure of 10− 4 N/m2. The as-grown samples were investigated by X-ray diffraction. The pattern indicated a highly oriented crystallographic growth of ZnTe (111) layer on CdTe (111) substrate. The current–voltage characteristics in both forward and reverse biasing were carried out in the temperature range from 300 down to 200 K. The dark forward current curves were definitely of the diode type in the forward direction. This behavior can be understood as the barrier at the interface limits forward and reverse carrier flow across the junction, where the built-in potential could be developed. Series resistance due to the neutral region was estimated at approximately 320 Ω and the activation energy of the carriers was calculated and found to be 0.11 ± 0.03 eV. The reverse current shows negative resistance behavior at low voltage range.